langchain-ai

langchain

The agent engineering platform.

137.3k stars22.7k forks872 watchers414 open issuesPythonMIT

EDITOR'S TAKE

The biggest LLM framework. Chains, agents, RAG pipelines, integrations with every model, vector DB, and tool. Strong ecosystem with LangGraph for agentic workflows. The criticism: for simple use cases the abstractions feel heavy and the API has churned across versions. Worth it once your AI stack outgrows direct API calls.

Use this if

You are building multi-step AI pipelines (agents, complex RAG, tool use) and need the ecosystem.

Skip if

You are just calling an LLM API and processing the response — use the native SDK directly.